When deceleration is requested for a vehicle, the rate at which brake fluid pressure is increased is generally dependent upon the rate at which the driver applies force to the brake pedal. In view of this, brake systems of conventional motor vehicles may include various measures in an attempt to reduce response time of the brake systems. For example, in a conventional motor vehicle, a brake system may pre-charge brake fluid having a fixed volume to an elevated pressure, such as behind a closed valve, or the system may move brake calipers closer to brake rotors in an attempt to slightly reduce response time of the brake system. Pre-charging of the brake fluid or moving the brake calipers closer to the brake rotors can occur, for example, when a driver quickly releases the accelerator pedal, which may indicate a desire to make a rapid stop.
However, pre-charging brake fluid is limited due to the fixed volume of brake fluid in the system. In particular, the moment a valve is opened and the volume of the pre-charged brake fluid changes, the pressure of the pre-charged brake fluid drops due to equalization on both sides of the valve. As a result, the effectiveness of pre-charging the brake fluid is diminished because only a portion of the pre-charged pressure, such as half, is delivered to the remainder of the hydraulic circuit upon opening the valve.
Thus, although brake systems have already contributed to significant improvements in enhancing brake responsiveness, further improvements may be made to braking systems for motor vehicles to further enhance the responsiveness of the braking system.